The combination effects of K2O and PbO poisoning on NH3-SCR TiO2-CeO2 catalyst

Abstract TiO2-CeO2 catalyst is a promising material for removal of NOx by NH3-SCR reaction. The poisonous substances existing in flue gas cause serious deactivation of the catalyst. However, most of the researches had focused on the effect of a single toxic component, while the actual flue gas contains multiple toxic components. In this work, the combination of K2O and PbO poisoning effects on NH3-SCR performance over the TiO2-CeO2 catalyst were investigated. A stronger poisonousness was found when K2O and PbO were simultaneously introduced. The characterization results showed that the coexistence of K2O and PbO hinder the transfer of electrons between TiO2 and CeO2, and worsen the decrease of surface adsorbed oxygen, the relative ratio of Ce3+, as well as the surface acidity. In situ DRIFTS results showed that the decrease of Bronsted acid caused by K and Pb was larger than Lewis acid. Additionally, the combination of K and Pb reduced the activation performance of NOx species. Finally, the TiO2-CeO2 catalyst’s Langmuir-Hinshelwood (L-H) mechanism did not change when K and Pb were introduced.